Veillonella, Firmicutes: Microbes disguised as Gram negatives. Issue 2 (September 2013)

• Record Type: Journal Article
• Authors: Vesth, Tammi; Ozen, Aslı; Andersen, Sandra; Kaas, Rolf; Lukjancenko, Oksana; Bohlin, Jon; Nookaew, Intawat; Wassenaar, Trudy; Ussery, David
• Is Part Of: Standards in genomic sciences. Volume 9:Issue 2(2013)
• Page Start: 431
• Page End: 448
• Publication Date: 2013-09
• Subjects: Genomics -- Periodicals; Genomics -- Periodicals; Genomics; Periodicals; 572.8605
• DOI: 10.4056/sigs.2981345
• Languages: English
• ISSNs: 1944-3277

Abstract

Abstract TheFirmicutes represent a major component of the intestinal microflora. The intestinalFirmicutes are a large, diverse group of organisms, many of which are poorly characterized due to their anaerobic growth requirements. Although mostFirmicutes are Gram positive, members of the classNegativicutes, including the genusVeillonella, stain Gram negative.Veillonella are among the most abundant organisms of the oral and intestinal microflora of animals and humans, in spite of being strict anaerobes. In this work, the genomes of 24Negativicutes, including eightVeillonella spp., are compared to 20 otherFirmicutes genomes; a further 101 prokaryotic genomes were included, covering 26 phyla. Thus a total of 145 prokaryotic genomes were analyzed by various methods to investigate the apparent conflict of theVeillonella Gram stain and their taxonomic position within theFirmicutes . Comparison of the genome sequences confirms that theNegativicutes are distantly related toClostridium spp., based on 16S rRNA, complete genomic DNA sequences, and a consensus tree based on conserved proteins. The genusVeillonella is relatively homogeneous: inter-genus pair-wise comparison identifies at least 1, 350 shared proteins, although less than half of these are found in any givenClostridium genome. Only 27 proteins are found conserved in all analyzed prokaryote genomes.Veillonella has distinct metabolic properties, and significant similarities to genomes ofProteobacteria are not detected, with the exception of a shared LPS biosynthesis pathway. The clade within the classNegativicutes to which the genusVeillonella belongs exhibits unique properties, most of which are in common with Gram-positives and some with Gram negatives. They are only distantly related toClostridia, but are even less closely related to Gram-negative species. Though theNegativicutes stain Gram-negative and possess two membranes, the genome and proteome analysis presented here confirm their place within the (mainly) Gram positive phylum of theFirmicutes . Further studies are required to unveil the evolutionary history of theVeillonella and otherNegativicutes .